A variety of different techniques for making shoe soles exist. Examples include injection molding the sole as a unitary piece, bonding layers of different material together to form the shoe's sole and use of vulcanization techniques.
In addition, a variety of different processing techniques have been used to provide the shoe's sole with particular characteristics and/or to obtain advantageous import duty rates that typically apply to shoes having an outsole in which at least 50% of the ground-contacting surface is made of a natural material. Examples of such processing techniques include molding fabric or other natural materials into the shoe's outsole and flocking the shoe's outsole with natural fabric fibers.
However, improvements in the structures of shoe outsoles, as well as the production techniques for making them, remain desirable.